The present invention relates to an externally-developed air bag device for protecting a pedestrian, an occupant of a bicycle or a motorcycle (hereinafter referred to as xe2x80x9cpedestrian or the likexe2x80x9d) when a car in running collides with the pedestrian, the bicycle, or the motorcycle.
FIG. 14(a) is a perspective view showing the front portion of the body of a car equipped with a conventional externally developed air bag device, and FIGS. 14(b) and 14(c) are sectional views thereof taken along the line Bxe2x80x94B in FIG. 14(a). Here, FIG. 14(b) shows a normal aspect of this externally-developed air bag device (i.e., the aspect thereof when the car is not in a state colliding with a pedestrian or the like), and FIG. 14(c) shows the aspect thereof when the air bag of this externally-developed air bag device has been developed.
The above-described externally-developed air bag 100 comprises an air bag 102 and an inflator 104 for inflating this air bag 102. The inflator 104 is disposed in a case (cowl top) 108 provided below the windshield (front window glass) 106 of the car, and normally the air bag 102 is accommodated in the cowl top 108 in a folded-up state.
The cowl top 108 includes a cowl top outer panel 112 exposed on the top surface of the front portion of the car body, and a cowl top inner panel 114 constituting the bottom portion of the cowl top 108. An opening for bulging out the air bag onto the top surface of the front portion of the car body is provided in the cowl top outer panel 112. The opening is disposed above the air bag 102 accommodated in the cowl top 108. Normally, a lid 116 is mounted over the opening so as to close the opening.
A contact detecting sensor 120 for detect that the car in running has collided with a pedestrian, a bicycle, or a motorcycle, is provided at the front end of the car body, such as the front bumper 118 of the car. The externally-developed air bag 100 is arranged so that, once the contact detecting sensor 120 has detected the occurrence of a collision, the inflator 104 comes into operation, and that a gas is introduced into the air bag 102 from the inflator 104, thereby inflating the air bag 102.
More specifically, once the car equipped with the externally-developed air bag 100 has collided with a pedestrian, a bicycle, or a motorcycle when the car is running, the contact detecting sensor 120 detects the occurrence of this collision, and the gas is introduced into the air bag 102 from the inflator 104, thereby inflating the air bag 102. The air bag 102 forces open the lid 116 mounted over the opening in the top surface of the cowl top 108, and bulges out onto the top surface of the front portion of the car body. Then, as shown in FIG. 14(c), the air bag 102 develops along the outer surface of the windshield 106 from the rear portion of a hood 110.
It is an object of the present invention to provide an externally-developed air bag device in which the air bag thereof is quickly inflated up to the completely developed shape.
The externally-developed air bag device according to the present invention comprises an air bag developable along the outer surface of a car; a case for accommodating the air bag; a lid for covering the case; an inflator for inflating the air bag. The above-described air bag has a long side direction and a short side direction intersecting the long side direction, in a flatly unfolded state. In this externally-developed air bag device, the air bag is made an intermediate folded body that is formed by folding back both end sides in the long side direction that run over from the case, toward the central side of the air bag. Then, the air bag is folded up in the short side direction and is accommodated into the case.
In this externally-developed air bag device, once the inflator has come into operation, a gas from the inflator is also directly introduced into both end sides of the air bag in the longitudinal direction (i.e., the portions running over from the case), thereby quickly inflating not only the central portion of the air bag but also both end sides thereof in the longitudinal direction.
In the present invention, it is preferable that the intermediate folded body of the air bag be folded up in the short side direction in a bellows shape or in a roll shape. This air bag folded up in a bellows shape or in a roll shape is smoothly inflated when the gas from the inflator is introduced thereinto.